WASHINGTON — The Pentagon announced Wednesday that three U.S. soldiers on reconnaissance patrol along the Macedonian border came under attack and were missing, and by early Thursday it was apparent that they had been captured by Serbian forces.

Serbian television showed video footage early Thursday of three men who Serbian officials claimed were the missing soldiers. The television report said the three were being held in Pristina, the Kosovar capital.

The video pictures showed the three men in camouflage uniforms, with blood on their faces, and they spoke with someone off camera.

The American soldiers, traveling in a military vehicle, were on a daytime reconnaissance mission in the Kumanovo area of Macedonia near the southern Yugoslav border when they reported by radio that they had come under small-arms fire and were surrounded by hostile forces. "No more was heard from the team," NATO said in a statement.

U.S. and British ground and helicopter forces and Macedonian army troops were searching for the team, part of the 350-soldier U.S. contingent of the 10,000-member NATO force patrolling the border in the former Yugoslav republic. Several U.S. Army teams had been on a reconnaissance mission together but had split up to engage in some rough-terrain training, the Pentagon said.

The incident marked the first reported armed encounter in the Kosovo conflict involving U.S. ground forces. It was unclear whether the American soldiers had come under fire from Yugoslav forces and whether the reconnaissance team was in Kosovo or on the Macedonian side of the border at the time.

Meanwhile, NATO moved to expand its military targets in the wake of mounting criticism that the weeklong bombing campaign had done nothing to deter Yugoslav President Slobodan Milosevic from pressing his military offensive against ethnic Albanians in Kosovo despite round-the-clock air attacks and cruise-missile assaults.

In Brussels, NATO Secretary General Javier Solana authorized military planners to "extend the range and tempo of operations to maximize the effectiveness of the campaign."

He rejected a Vatican plea for a bombing halt during the Easter weekend and said the alliance remains firm in its resolve to break the Serbian leader.

Eight days into the allied air campaign, the assaults appear to have united the Yugoslav people behind Milosevic, a leader who was not widely loved before the bombing began, and revived bitter criticism reminiscent of the Cold War from Belgrade all the way to Moscow.

Russia announced it would send an intelligence ship to the region to monitor the NATO raids and would put as many as seven other warships on alert or actually send them into the region. The White House said the message was not clear, but officials voiced concern that the Russians would be flexing naval muscle after they had already announced they planned to take no military action.

White House officials said they were prepared for a long-term bombing effort that would continue until Milosevic ends the repression of the Albanians. Since Tuesday, they have been saying they never expected to achieve their goal with just a few days of bombing.

"We have no firm timetable for this," a White House spokesman said. "Either President Milosevic is going to change his calculation, or we are going to continually and systematically hit his military and deprive him of the ability to impose his will."

While the campaign may not have had its intended effect on Milosevic, it has changed the face of the Balkans, injected the threat of war across one of the most explosive regions on earth and prompted an exodus of refugees straining the tattered resources of every nation that abuts the Kosovo province.

The refugee crisis deepened Wednesday, with the United Nations estimating 130,000 people have fled Kosovo to Albania, Macedonia and Montenegro since the bombing campaign and stepped-up repression by Serbian troops and special police units began eight days ago.

The Clinton administration pledged an additional $50 million to assist in refugee relief efforts.

In Kosovo, Serbian troops were methodically destroying the birth, marriage, property and financial records of ethnic Albanians forced from the southern province, said NATO spokesman Jamie Shea. Their passports, personal papers, even their auto license plates, were being seized before they passed through border crossings.

"This is a kind of Orwellian scenario of attempting to deprive a people and a culture of the sense of past and the sense of community on which it depends," Shea said in Brussels.